Internet-Draft ACVP KDFs August 2020
Celi Expires 11 February 2021 [Page]
Workgroup:
Network Working Group
Internet-Draft:
draft-gold-acvp-kdf-01
:
Published:
Intended Status:
Informational
Expires:
Author:
C. Celi, Ed.

ACVP SP800-108 Key Derivation Function JSON Specification

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.

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This Internet-Draft will expire on 11 February 2021.

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Table of Contents

1. Acknowledgements

There are no acknowledgements.

2. Abstract

This document defines the JSON schema for testing SP800-108 KDF implementations with the ACVP specification.

3. Introduction

The Automated Crypto Validation Protocol (ACVP) defines a mechanism to automatically verify the cryptographic implementation of a software or hardware crypto module. The ACVP specification defines how a crypto module communicates with an ACVP server, including crypto capabilities negotiation, session management, authentication, vector processing and more. The ACVP specification does not define algorithm specific JSON constructs for performing the crypto validation. A series of ACVP sub-specifications define the constructs for testing individual crypto algorithms. Each sub-specification addresses a specific class of crypto algorithms. This sub-specification defines the JSON constructs for testing SP800-108 KDF implementations using ACVP.

4. Terms and definitions

No terms and definitions are listed in this document.

5. Supported SP800-108 KDFs

The following key derivation functions MAY be advertised by the ACVP compliant cryptographic module:

6. Test Types and Test Coverage

7. Capabilities Registration

ACVP requires crypto modules to register their capabilities. This allows the crypto module to advertise support for specific algorithms, notifying the ACVP server which algorithms need test vectors generated for the validation process. This section describes the constructs for advertising support of KDF 108 algorithms to the ACVP server.

The algorithm capabilities MUST be advertised as JSON objects within the 'algorithms' value of the ACVP registration message. The 'algorithms' value is an array, where each array element is an individual JSON object defined in this section. The 'algorithms' value is part of the 'capability_exchange' element of the ACVP JSON registration message. See the ACVP specification [ACVP] for more details on the registration message.

7.1. Prerequisites

Each algorithm implementation MAY rely on other cryptographic primitives. For example, RSA Signature algorithms depend on an underlying hash function. Each of these underlying algorithm primitives must be validated, either separately or as part of the same submission. ACVP provides a mechanism for specifying the required prerequisites:

Prerequisites, if applicable, MUST be submitted in the registration as the prereqVals JSON property array inside each element of the algorithms array. Each element in the prereqVals array MUST contain the following properties

Table 1: Prerequisite Properties
JSON Property Description JSON Type
algorithm a prerequisite algorithm string
valValue algorithm validation number string

A "valValue" of "same" SHALL be used to indicate that the prerequisite is being met by a different algorithm in the capability exchange in the same registration.

An example description of prerequisites within a single algorithm capability exchange looks like this

"prereqVals":
[
  {
    "algorithm": "Alg1",
    "valValue": "Val-1234"
  },
  {
    "algorithm": "Alg2",
    "valValue": "same"
  }
]
Figure 1

7.2. Required Prerequisite Algorithms for SP800-108 KDF Validations

Each SP800-108 KDF implementation relies on other cryptographic primitives. For example, the KDF must utilize an underlying MAC algorithm. Each of these underlying algorithm primitives must be validated, either separately or as part of the same submission. ACVP provides a mechanism for specifying the required prerequisites:

Table 2: SP800-108 KDF Required Prerequisites
JSON Value Description JSON Type Valid Values
algorithm A prerequisite algorithm string AES, DRBG, CMAC, HMAC
valValue Algorithm validation number string Actual number or "same"
prereqAlgVal Prerequisite algorithm validation object with algorithm and valValue properties See above
prereqVals Prerequisite algorithm validations array of prereqAlgVal objects See above

7.3. SP800-108 KDF Algorithm Capabilities Registration

Each algorithm capability advertised is a self-contained JSON object using the following values.

Table 3: SP800-108 KDF Algorithm Capabilities JSON Values
JSON Value Description JSON Type Valid Values
algorithm The KDF to be validated. string KDF
revision The algorithm testing revision to use. string "1.0"
prereqVals Prerequisite algorithm validations array of prereqAlgVal objects See Section 7.2
capabilities Array of JSON objects, each with fields pertaining to the KDF mode identified uniquely by the combination of the "kdfMode" and indicated properties array of JSON objects See Section 7.5

7.4. Supported SP800-108 KDF Modes

The following SP800-108 KDF modes may be advertised by the ACVP compliant crypto module:

  • counter

  • feedback

  • double pipeline iteration

7.5. Supported KDF Modes Capabilities

The KDF mode capabilities are advertised as JSON objects within the 'capabilities' value of the ACVP registration message - see Table 2. The 'capabilities' value is an array, where each array element is a JSON object corresponding to a particular KDF mode defined in this section. The 'capabilities' value is part of the 'capability_exchange' element of the ACVP JSON registration message. See the ACVP specification [ACVP] for details on the registration message.

Each KDF mode's capabilities are advertised as JSON objects.

The complete list of KDF key generation capabilities may be advertised by the ACVP compliant crypto module:

Table 4: KDF Mode Capabilities
JSON Value Description JSON Type Valid Values
kdfMode The type of SP800-108 KDF string See Section 7.4
macMode The MAC algorithm used string See Section 7.6
supportedLengths The key lengths supported in bits domain Min: 1, Max: 4096
fixedDataOrder Describes where the counter appears in the fixed data array Any non-empty subset of {"none", "after fixed data", "before fixed data", "middle fixed data", "before iterator"}
counterLength The length of the counter in bits array Any non-empty subset of {0, 8, 16, 24, 32}
supportsEmptyIv Whether or not the IUT supports an empty IV boolean true/false
requiresEmptyIv Whether or not the IUT requires an empty IV boolean true/false

7.6. Supported SP800-108 KDF MACs

The following MAC functions MAY be advertised by an ACVP compliant client

  • CMAC-AES128

  • CMAC-AES192

  • CMAC-AES256

  • CMAC-TDES

  • HMAC-SHA1

  • HMAC-SHA2-224

  • HMAC-SHA2-256

  • HMAC-SHA2-384

  • HMAC-SHA2-512

  • HMAC-SHA2-512/224

  • HMAC-SHA2-512/256

  • HMAC-SHA3-224

  • HMAC-SHA3-256

  • HMAC-SHA3-384

  • HMAC-SHA3-512

7.7. Registration Example

A registration SHALL use these properties

Table 5: Registration Properties
JSON Property Description JSON Type Valid Values
algorithm Name of the algorithm to be validated string "KDF"
revision ACVP Test version string "1.0"
prereqVals Prerequisites of the algorithm object See Section 7.1
capabilities Properties of the algorithm and mode the IUT supports array See Section 7.5

8. Test Vectors

The ACVP server provides test vectors to the ACVP client, which are then processed and returned to the ACVP server for validation. A typical ACVP validation test session would require multiple test vector sets to be downloaded and processed by the ACVP client. Each test vector set represents an individual algorithm defined during the capability exchange. This section describes the JSON schema for a test vector set used with SP800-108 KDF algorithms.

The test vector set JSON schema is a multi-level hierarchy that contains meta data for the entire vector set as well as individual test vectors to be processed by the ACVP client. The following table describes the JSON elements at the top level of the hierarchy.

Table 6: Top Level Test Vector JSON Elements
JSON Values Description JSON Type
acvVersion Protocol version identifier string
vsId Unique numeric vector set identifier integer
algorithm Algorithm defined in the capability exchange string
mode Mode defined in the capability exchange string
revision Protocol test revision selected string
testGroups Array of test groups containing test data, see Section 8.1 array

An example of this would look like this

{
  "acvVersion": "version",
  "vsId": 1,
  "algorithm": "Alg1",
  "mode": "Mode1",
  "revision": "Revision1.0",
  "testGroups": [ ... ]
}
Figure 2

8.1. Test Groups

The testGroups element at the top level in the test vector JSON object is an array of test groups. Test vectors are grouped into similar test cases to reduce the amount of data transmitted in the vector set. For instance, all test vectors that use the same key size would be grouped together. The Test Group JSON object contains meta data that applies to all test vectors within the group. The following table describes the the secure hash JSON elements of the Test Group JSON object.

The prompt test group for KDF is as follows:

Table 7: Test Group JSON Object
JSON Values Description JSON Type
tgId Test group identifier integer
kdfMode The kdfMode used for the test group string
macMode Psuedorandom function HMAC or CMAC used string
counterLocation "none", "after fixed data", "before fixed data", "middle fixed data", or "before iterator" string
keyOutLength Expected length of the derived key in bits integer
counterLength Expected length of the counter in bits integer
zeroLengthIv Whether or not the group utilizes a null IV boolean
testType Describes the operation being performed string
No tests Array of individual test cases

The 'tgId', 'testType' and 'tests' objects MUST appear in every test group element communicated from the server to the client as a part of a prompt. Other properties are dependent on which 'testType' the group is addressing.

8.2. Test Cases

Each test group contains an array of one or more test cases. Each test case is a JSON object that represents a single test vector to be processed by the ACVP client. The following table describes the JSON elements for each SP800-108 KDF test vector.

Table 8: Test Case JSON Object
JSON Values Description JSON Type
tcId Test case idenfitier integer
keyIn Input key hex
iv The initialization vector used only for feedback KDFs hex
deferred Indicates the client is required to provide additional input values to complete the test case boolean

9. Responses

After the ACVP client downloads and processes a vector set, it must send the response vectors back to the ACVP server. The following table describes the JSON object that represents a vector set response.

Table 9: Vector Set Response JSON Object
JSON Property Description JSON Type
acvVersion The version of the protocol string
vsId The vector set identifier integer
testGroups The test group data array

An example of this is the following

{
        "acvVersion": "version",
        "vsId": 1,
        "testGroups": [ ... ]
}
Figure 3

The testGroups section is used to organize the ACVP client response in a similar manner to how it receives vectors. Several algorithms SHALL require the client to send back group level properties in their response. This structure helps accommodate that.

Table 10: Vector Set Group Response JSON Object
JSON Property Description JSON Type
tgId The test group identifier integer
tests The test case data array

An example of this is the following

{
        "tgId": 1,
        "tests": [ ... ]
}
Figure 4

The following table describes the JSON object that represents a test case response for a SP800-108 KDF.

Table 11: Test Case Results JSON Object
JSON Property Description JSON Type
tcId The test case identifier integer
breakLocation The bit location in the fixed data where the counter is placed integer
fixedData The fixed data used hex
keyOut The outputted key hex

10. Security Considerations

There are no additional security considerations outside of those outlined in the ACVP document.

11. IANA Considerations

This document does not require any action by IANA.

12. Example SP800-108 KDF Capabilities JSON Object

The following is a example JSON object advertising support for KDF.

    {
       "algorithm": "KDF",
       "revision": "1.0",
       "prereqVals": [
           {
               "algorithm": "SHA",
               "valValue": "123456"
           },
           {
               "algorithm": "DRBG",
               "valValue": "123456"
           }
       ],
       "capabilities": [
           {
               "kdfMode": "counter",
               "macMode": [
                   "CMAC-AES128",
                   "CMAC-AES192",
                   "CMAC-AES256",
                   "CMAC-TDES",
                   "HMAC-SHA-1",
                   "HMAC-SHA2-224",
                   "HMAC-SHA2-256",
                   "HMAC-SHA2-384",
                   "HMAC-SHA2-512"
               ],
               "supportedLengths": [
                   {
                       "min": 8,
                       "max": 1024,
                       "increment": 1
                   }
               ],
               "fixedDataOrder": [
                   "after fixed data",
                   "before fixed data",
                   "middle fixed data"
               ],
               "counterLength": [
                   8,
                   16,
                   24,
                   32
               ],
               "supportsEmptyIv": false
           },
           {
               "kdfMode": "feedback",
               "macMode": [
                   "CMAC-AES128",
                   "CMAC-AES192",
                   "CMAC-AES256",
                   "CMAC-TDES",
                   "HMAC-SHA-1",
                   "HMAC-SHA2-224",
                   "HMAC-SHA2-256",
                   "HMAC-SHA2-384",
                   "HMAC-SHA2-512"
               ],
               "supportedLengths": [
                   {
                       "min": 8,
                       "max": 1024,
                       "increment": 1
                   }
               ],
               "fixedDataOrder": [
                   "none",
                   "after fixed data",
                   "before fixed data",
                   "before iterator"
               ],
               "counterLength": [
                   0,
                   8,
                   16,
                   24,
                   32
               ],
               "supportsEmptyIv": true,
               "requiresEmptyIv": false
           },
           {
               "kdfMode": "double pipeline iteration",
               "macMode": [
                   "CMAC-AES128",
                   "CMAC-AES192",
                   "CMAC-AES256",
                   "CMAC-TDES",
                   "HMAC-SHA-1",
                   "HMAC-SHA2-224",
                   "HMAC-SHA2-256",
                   "HMAC-SHA2-384",
                   "HMAC-SHA2-512"
               ],
               "supportedLengths": [
                   {
                       "min": 8,
                       "max": 1024,
                       "increment": 1
                   }
               ],
               "fixedDataOrder": [
                   "none",
                   "after fixed data",
                   "before fixed data",
                   "before iterator"
               ],
               "counterLength": [
                   0,
                   8,
                   16,
                   24,
                   32
               ],
               "supportsEmptyIv": false
           }
       ]
   }
Figure 5

13. Example Test Vectors JSON Object

The following is a example JSON object for SP800-108 KDF test vectors sent from the ACVP server to the crypto module.

[{
                "acvVersion": "0..54"
        },
        {
                "vsId": 1564,
                "algorithm": "counterMode",
                "revision": "1.0",
                "testGroups": [{
                        "tgId": 1,
                        "kdfMode": "counter",
                        "macMode": "CMAC-AES128",
                        "counterLocation": "after fixed data",
                        "keyOutLength": 1024,
                        "counterLength": 8,
                        "tests": [{
                                        "tcId": 1,
                                        "keyIn": "5DA38931E8D9174BC3279C8942D2DB82",
                                        "deferred": false
                                },
                                {
                                        "tcId": 2,
                                        "keyIn": "58F5426A40E3D5D2C94F0F97EB30C739",
                                        "deferred": false
                                }
                        ]
                }]
        }
]
Figure 6

14. Example Test Results JSON Object

The following is a example JSON object for SP800-108 KDF test results sent from the crypto module to the ACVP server.

[{
                "acvVersion": <acvp-version>
        },
        {
                "vsId": 1564,
                "testGroups": [{
                        "tgId": 1,
                        "tests": [{
                                "tcId": 1,
                                "keyOut": "94D58F22FA9092B0375F7EE6841B6775226703E3232BF9CF496E4EF3CDE1037765DDC060C08C9B3A845E288EED171535EBA97D23DCF8F6D2D4CF9D980CB4F6D270D3A7859B1FE2BFCA81F0702B5767E35BE9B96BA65C5263EB0DECD5FA721FFA57CE208F53F910DB6087E93BEE1A24E790E1DF02C140E89E04DF5299A63B71DA",
                                "fixedData": "FBF14DF02EE6C7DABCA6EF9AF59BB9A2"
                        }]
                }]
        }
]
Figure 7

15. Normative references

[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", IETF RFC 2119, IETF RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC7991]
Hoffman, P., "The "xml2rfc" Version 3 Vocabulary", IETF RFC 7991, IETF RFC 7991, DOI 10.17487/RFC7991, , <https://www.rfc-editor.org/info/rfc7991>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", IETF RFC 8174, IETF RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
[ACVP]
NIST, "Automatic Cryptographic Validation Protocol", ACVP ACVP, .

Author's Address

Christopher Celi (editor)